Service schematic for the HTC Desire 816 smartphone in a 1.66 MB PDF, with a website tag appended to the file name. No board number or revision is given, so compare the PCB markings with the drawings before trusting the component references. A phone schematic like this is used to follow the battery and charging path, locate the power management IC and trace signals to the display, camera and SIM connectors when diagnosing dead or partly working handsets. It opens in any standard PDF viewer.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @mobileshematic. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.